The answer to the summons

Psalm 136 may be considered as the answer to this summons. It is
characterised by the formulary, as often noticed, the expression of
Jehovah's unchanging goodness to Israel in spite of all: "His mercy
endureth for ever." It celebrates Him as Creator, God of gods, the
Deliverer of Israel, who had led them through the wilderness, as Him
who by power slaying mighty kings had given them the inheritance of
the land; and who, finally, remembering them in their low estate,
had redeemed them from it, and now supplied every living thing with
food, the God of heaven. This, in a certain sense, closes the
historical psalms.

Sorrows; Jehovah's ways; millennial praises

We have then a kind of supplementary series: first, of their
characteristic sorrows and Jehovah's ways in the latter days, and
then of millennial praises. These sorrows are from Psalm 137 to
Psalm 144 the latter, however, being the expectation of deliverance
and blessing. Psalm 139 also has a peculiar character, as will be at
once seen.